The long term objective of this research project is to serve as the Visual Field Reading Center for the Optic Neuritis Treatment Trial. Specific aims of the project are: (1) To receive the visual fields from all the clinical centers and transfer and compact the data into a format that can be used by the Data Coordinating Center to determine whether there is a statistically significant difference between the visual fields recorded in the three treatment groups. (2) To assess the reliability of the visual fields performed at each clinical center. (3) To define the natural history of visual field pathology in patients with optic neuritis. The significance of the Optic Neuritis Treatment Trial has been reviewed in that protocol. The key element of the Optic Neuritis Treatment Trial is to define whether a difference exists between the three treatment groups. In addition, the natural history of optic neuritis visual field pathology has not been previously defined. Quantitative automated perimetry will allow an excellent means to study this problem.